通过 Kubeadm 安装 K8S 与高可用


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目录[-]


环境介绍

  • CentOS: 7.6
  • Docker: 18.06.1-ce
  • Kubernetes: 1.13.4
  • Kuberadm: 1.13.4
  • Kuberlet: 1.13.4
  • Kuberctl: 1.13.4

部署介绍:

创建高可用首先先有一个 Master 节点,然后再让其他服务器加入组成三个 Master 节点高可用,然后再讲工作节点 Node 加入。下面将描述每个节点要执行的步骤:

  • Master01: 二、三、四、五、六、七、八、九、十一
  • Master02、Master03: 二、三、五、六、四、九
  • node01、node02: 二、五、六、九

集群架构:


一、kuberadm 简介

Kuberadm 作用

Kubeadm 是一个工具,它提供了 kubeadm init 以及 kubeadm join 这两个命令作为快速创建 kubernetes 集群的最佳实践。

kubeadm 通过执行必要的操作来启动和运行一个最小可用的集群。它被故意设计为只关心启动集群,而不是之前的节点准备工作。同样的,诸如安装各种各样值得拥有的插件,例如 Kubernetes Dashboard、监控解决方案以及特定云提供商的插件,这些都不在它负责的范围。

相反,我们期望由一个基于 kubeadm 从更高层设计的更加合适的工具来做这些事情;并且,理想情况下,使用 kubeadm 作为所有部署的基础将会使得创建一个符合期望的集群变得容易。

Kuberadm 功能

  • kubeadm init: 启动一个 Kubernetes 主节点
  • kubeadm join: 启动一个 Kubernetes 工作节点并且将其加入到集群
  • kubeadm upgrade: 更新一个 Kubernetes 集群到新版本
  • kubeadm config: 如果使用 v1.7.x 或者更低版本的 kubeadm 初始化集群,您需要对集群做一些配置以便使用 kubeadm upgrade 命令
  • kubeadm token: 管理 kubeadm join 使用的令牌
  • kubeadm reset: 还原 kubeadm init 或者 kubeadm join 对主机所做的任何更改
  • kubeadm version: 打印 kubeadm 版本
  • kubeadm alpha: 预览一组可用的新功能以便从社区搜集反馈

功能版本

Area Maturity Level
Command line UX GA
Implementation GA
Config file API beta
CoreDNS GA
kubeadm alpha subcommands alpha
High availability alpha
DynamicKubeletConfig alpha
Self-hosting alpha

二、前期准备

1、虚拟机分配说明

地址 主机名 内存&CPU 角色
192.168.2.10 vip
192.168.2.11 k8s-master-01 2C & 2G master
192.168.2.12 k8s-master-02 2C & 2G master
192.168.2.13 k8s-master-03 2C & 2G master
192.168.2.21 k8s-node-01 2c & 4G node
192.168.2.22 k8s-node-02 2c & 4G node

2、各个节点端口占用

  • Master 节点
规则 方向 端口范围 作用 使用者
TCP Inbound 6443* Kubernetes API server All
TCP Inbound 2379-2380 etcd server client API kube-apiserver, etcd
TCP Inbound 10250 Kubelet API Self, Control plane
TCP Inbound 10251 kube-scheduler Self
TCP Inbound 10252 kube-controller-manager Sel
  • node 节点
规则 方向 端口范围 作用 使用者
TCP Inbound 10250 Kubelet API Self, Control plane
TCP Inbound 30000-32767 NodePort Services** All

3、基础环境设置

Kubernetes 需要一定的系统环境来保证正常运行,如各个节点时间同步,主机名称解析,关闭防火墙等等。

主机名称解析

修改hosts

分别进入不同服务器,进入 /etc/hosts 进行编辑

vim /etc/hosts

加入下面内容:

192.168.2.10    master.k8s.io      k8s-vip
192.168.2.11    master01.k8s.io    k8s-master-01
192.168.2.12    master02.k8s.io    k8s-master-02
192.168.2.13    master03.k8s.io    k8s-master-03
192.168.2.21    node01.k8s.io      k8s-node-01
192.168.2.22    node02.k8s.io      k8s-node-02

修改hostname

分别进入不同的服务器,修改 hostname 名称

# 修改 192.168.2.11 服务器
hostnamectl  set-hostname  k8s-master-01
# 修改 192.168.2.12 服务器
hostnamectl  set-hostname  k8s-master-02
# 修改 192.168.2.13 服务器
hostnamectl  set-hostname  k8s-master-03

# 修改 192.168.2.21 服务器
hostnamectl  set-hostname  k8s-node-01
# 修改 192.168.2.22 服务器
hostnamectl  set-hostname  k8s-node-02

主机时间同步

将各个服务器的时间同步,并设置开机启动同步时间服务

systemctl start chronyd.service
systemctl enable chronyd.service

关闭防火墙服务

systemctl stop firewalld
systemctl disable firewalld

关闭并禁用SELinux

# 关闭selinux
setenforce 0

# 编辑/etc/sysconfig selinux 文件,以彻底禁用 SELinux
sed -i 's/^SELINUX=enforcing$/SELINUX=disabled/' /etc/selinux/config

# 查看selinux状态
getenforce 

禁用 Swap 设备

Kubeadm 默认会预先检当前主机是否禁用了 Swap 设备,如果启动了 Swap 将导致安装不能正常进行,所以需要禁用所有的 Swap 设备。

# 关闭当前已启用的所有 Swap 设备
swapoff -a && sysctl -w vm.swappiness=0
# 编辑 fstab 配置文件,注释掉标识为 Swap 设备的所有行
vi /etc/fstab

设置系统参数

设置允许路由转发,不对 bridge 的数据进行处理,这里创建 /etc/sysctl.d/k8s.conf 文件,在里面加入对应配置。

vim /etc/sysctl.d/k8s.conf

加入下面内容:

net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1

挂载br_netfilter

modprobe br_netfilter

使配置生效

sysctl -p /etc/sysctl.d/k8s.conf

sysctl命令:用于运行时配置内核参数

查看是否生成相关文件

ls /proc/sys/net/bridge

资源配置文件

/etc/security/limits.conf 是 Linux 资源使用配置文件,用来限制用户对系统资源的使用

echo "* soft nofile 65536" >> /etc/security/limits.conf
echo "* hard nofile 65536" >> /etc/security/limits.conf
echo "* soft nproc 65536"  >> /etc/security/limits.conf
echo "* hard nproc 65536"  >> /etc/security/limits.conf
echo "* soft  memlock  unlimited"  >> /etc/security/limits.conf
echo "* hard memlock  unlimited"  >> /etc/security/limits.conf

安装依赖包以及相关工具

yum install -y epel-release
yum install -y yum-utils device-mapper-persistent-data lvm2 net-tools conntrack-tools wget vim  ntpdate libseccomp libtool-ltdl

三、安装Keepalived

  • keepalived 介绍: 是集群管理中保证集群高可用的一个服务软件,其功能类似于heartbeat,用来防止单点故障
  • Keepalived 作用: 为haproxy提供vip(192.168.2.10)在三个haproxy实例之间提供主备,降低当其中一个haproxy失效的时对服务的影响。

1、yum安装Keepalived

# 安装keepalived
yum install -y keepalived

2、配置Keepalived

cat <<EOF > /etc/keepalived/keepalived.conf
! Configuration File for keepalived

# 主要是配置故障发生时的通知对象以及机器标识。
global_defs {
   # 标识本节点的字条串,通常为 hostname,但不一定非得是 hostname。故障发生时,邮件通知会用到。
   router_id LVS_k8s
}

# 用来做健康检查的,当时检查失败时会将 vrrp_instance 的 priority 减少相应的值。
vrrp_script check_haproxy {
    script "killall -0 haproxy"   #根据进程名称检测进程是否存活
    interval 3
    weight -2
    fall 10
    rise 2
}

# rp_instance用来定义对外提供服务的 VIP 区域及其相关属性。
vrrp_instance VI_1 {
    state MASTER   #当前节点为MASTER,其他两个节点设置为BACKUP
    interface ens33 #改为自己的网卡
    virtual_router_id 51
    priority 250
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 35f18af7190d51c9f7f78f37300a0cbd
    }
    virtual_ipaddress {
        192.168.2.10   #虚拟ip,即VIP
    }
    track_script {
        check_haproxy
    }

}
EOF

当前节点的配置中 state 配置为 MASTER,其它两个节点设置为 BACKUP

配置说明

  • virtual_ipaddress: vip
  • track_script: 执行上面定义好的检测的script
  • interface: 节点固有IP(非VIP)的网卡,用来发VRRP包。
  • virtual_router_id: 取值在0-255之间,用来区分多个instance的VRRP组播
  • advert_int: 发VRRP包的时间间隔,即多久进行一次master选举(可以认为是健康查检时间间隔)。
  • authentication: 认证区域,认证类型有PASS和HA(IPSEC),推荐使用PASS(密码只识别前8位)。
  • state: 可以是MASTER或BACKUP,不过当其他节点keepalived启动时会将priority比较大的节点选举为MASTER,因此该项其实没有实质用途。
  • priority: 用来选举master的,要成为master,那么这个选项的值最好高于其他机器50个点,该项取值范围是1-255(在此范围之外会被识别成默认值100)。

3、启动Keepalived

# 设置开机启动
systemctl enable keepalived
# 启动keepalived
systemctl start keepalived
# 查看启动状态
systemctl status keepalived

4、查看网络状态

kepplived 配置中 state 为 MASTER 的节点启动后,查看网络状态,可以看到虚拟IP已经加入到绑定的网卡中

ip address show ens33

当关掉当前节点的keeplived服务后将进行虚拟IP转移,将会推选state 为 BACKUP 的节点的某一节点为新的MASTER,可以在那台节点上查看网卡,将会查看到虚拟IP

四、安装haproxy

此处的haproxy为apiserver提供反向代理,haproxy将所有请求轮询转发到每个master节点上。相对于仅仅使用keepalived主备模式仅单个master节点承载流量,这种方式更加合理、健壮。

1、yum安装haproxy

yum install -y haproxy

2、配置haproxy

cat > /etc/haproxy/haproxy.cfg << EOF
#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
    # to have these messages end up in /var/log/haproxy.log you will
    # need to:
    # 1) configure syslog to accept network log events.  This is done
    #    by adding the '-r' option to the SYSLOGD_OPTIONS in
    #    /etc/sysconfig/syslog
    # 2) configure local2 events to go to the /var/log/haproxy.log
    #   file. A line like the following can be added to
    #   /etc/sysconfig/syslog
    #
    #    local2.*                       /var/log/haproxy.log
    #
    log         127.0.0.1 local2
    
    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon 
       
    # turn on stats unix socket
    stats socket /var/lib/haproxy/stats
#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------  
defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000
#---------------------------------------------------------------------
# kubernetes apiserver frontend which proxys to the backends
#--------------------------------------------------------------------- 
frontend kubernetes-apiserver
    mode                 tcp
    bind                 *:16443
    option               tcplog
    default_backend      kubernetes-apiserver    
#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
backend kubernetes-apiserver
    mode        tcp
    balance     roundrobin
    server      master01.k8s.io   192.168.2.11:6443 check
    server      master02.k8s.io   192.168.2.12:6443 check
    server      master03.k8s.io   192.168.2.13:6443 check
#---------------------------------------------------------------------
# collection haproxy statistics message
#---------------------------------------------------------------------
listen stats
    bind                 *:1080
    stats auth           admin:awesomePassword
    stats refresh        5s
    stats realm          HAProxy\ Statistics
    stats uri            /admin?stats
EOF

haproxy配置在其他master节点上(192.168.2.12和192.168.2.13)相同

3、启动并检测haproxy

# 设置开机启动
systemctl enable haproxy
# 开启haproxy
systemctl start haproxy
# 查看启动状态
systemctl status haproxy

4、检测haproxy端口

ss -lnt | grep -E "16443|1080"

显示:

五、安装Docker (所有节点)

1、移除之前安装过的Docker

sudo yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-selinux \
                  docker-engine-selinux \
                  docker-ce-cli \
                  docker-engine

查看还有没有存在的docker组件

rpm -qa|grep docker

有则通过命令 yum -y remove XXX 来删除,比如:

yum remove docker-ce-cli

2、配置docker的yum源

安装 Docker 可以从官方 yum 源下载对应应用,不过由于官方下载速度比较慢,所以推荐用阿里镜像源:

sudo yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

3、安装Docker:

显示docker-ce所有可安装版本:

yum list docker-ce --showduplicates | sort -r

安装指定docker版本

sudo yum install docker-ce-18.06.1.ce-3.el7 -y

设置镜像存储目录

找到大点的挂载的目录进行存储

# 修改docker配置
vi /lib/systemd/system/docker.service

#找到 ExecStart 这行,王后面加上存储目录,例如这里是 --graph /apps/docker
ExecStart=/usr/bin/docker --graph /apps/docker

启动docker并设置docker开机启动

systemctl enable docker
systemctl start docker

4、确认一下 iptables

确认一下iptables filter表中FOWARD链的默认策略(pllicy)为ACCEPT。

iptables -nvL

显示:

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 DOCKER-USER  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
    0     0 DOCKER-ISOLATION-STAGE-1  all  --  *      *       0.0.0.0/0            0.0.0.0/0           
    0     0 ACCEPT     all  --  *      docker0  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
    0     0 DOCKER     all  --  *      docker0  0.0.0.0/0            0.0.0.0/0           
    0     0 ACCEPT     all  --  docker0 !docker0  0.0.0.0/0            0.0.0.0/0           
    0     0 ACCEPT     all  --  docker0 docker0  0.0.0.0/0            0.0.0.0/0            

Docker从1.13版本开始调整了默认的防火墙规则,禁用了iptables filter表中FOWARD链,这样会引起Kubernetes集群中跨Node的Pod无法通信。但这里通过安装docker 1806,发现默认策略又改回了ACCEPT,这个不知道是从哪个版本改回的,因为我们线上版本使用的1706还是需要手动调整这个策略的。

六、安装kubeadm、kubelet

  • 需要在每台机器上都安装以下的软件包:

    • kubeadm: 用来初始化集群的指令。
    • kubelet: 在集群中的每个节点上用来启动 pod 和 container 等。
    • kubectl: 用来与集群通信的命令行工具。

1、配置可用的国内yum源用于安装:

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

2、安装kubelet

查看kubelet版本列表

yum list kubectl --showduplicates | sort -r 

安装kubelet

yum install -y kubectl-1.13.4-0

3、安装kubelet

查看kubelet版本列表

yum list kubelet --showduplicates | sort -r 

安装kubelet

yum install -y kubelet-1.13.4-0

启动kubelet并设置开机启动

systemctl enable kubelet 
systemctl start kubelet

检查状态

检查状态,发现是failed状态,正常,kubelet会10秒重启一次,等初始化master节点后即可正常

systemctl status kubelet

4、安装kubeadm

查看kubeadm版本列表

yum list kubeadm --showduplicates | sort -r 

安装kubeadm

yum install -y kubeadm-1.13.4-0

安装 kubeadm 时候会默认安装 kubectl ,所以不需要单独安装kubectl

4、重启服务器

为了防止发生某些未知错误,这里我们重启下服务器,方便进行后续操作

reboot

七、初始化第一个kubernetes master节点

因为需要绑定虚拟IP,所以需要首先先查看虚拟IP启动这几台master机子哪台上

ip address show ens33

显示:

 ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:7e:65:b3 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.11/24 brd 192.168.2.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.2.10/32 scope global ens33
       valid_lft forever preferred_lft forever

可以看到 10虚拟ip 和 11的ip 在一台机子上,所以初始化kubernetes第一个master要在master01机子上进行安装

1、创建kubeadm配置的yaml文件

cat > kubeadm-config.yaml << EOF
apiServer:
  certSANs:
    - k8s-master-01
    - k8s-master-02
    - k8s-master-03
    - master.k8s.io
    - 192.168.2.10
    - 192.168.2.11
    - 192.168.2.12
    - 192.168.2.13
    - 127.0.0.1
  extraArgs:
    authorization-mode: Node,RBAC
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta1
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: "master.k8s.io:16443"
controllerManager: {}
dns: 
  type: CoreDNS
etcd:
  local:    
    dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: v1.13.4
networking: 
  dnsDomain: cluster.local  
  podSubnet: 10.20.0.0/16
  serviceSubnet: 10.10.0.0/16
scheduler: {}
EOF

以下两个地方设置: - certSANs: 虚拟ip地址(为了安全起见,把所有集群地址都加上) - controlPlaneEndpoint: 虚拟IP:监控端口号

配置说明:

  • imageRepository: registry.aliyuncs.com/google_containers (使用阿里云镜像仓库)
  • podSubnet: 10.20.0.0/16 (pod地址池)
  • serviceSubnet: 10.10.0.0/16

2、初始化第一个master节点

kubeadm init --config kubeadm-config.yaml 

日志:

Your Kubernetes master has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

You can now join any number of machines by running the following on each node
as root:

  kubeadm join master.k8s.io:16443 --token dm3cw1.kw4hq84ie1376hji --discovery-token-ca-cert-hash sha256:f079b624773145ba714b56e177f52143f90f75a1dcebabda6538a49e224d4009

在此处看日志可以知道,通过

kubeadm join master.k8s.io:16443 --token dm3cw1.kw4hq84ie1376hji --discovery-token-ca-cert-hash sha256:f079b624773145ba714b56e177f52143f90f75a1dcebabda6538a49e224d4009

来让节点加入集群

3、配置kubectl环境变量

配置环境变量

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

4、查看组件状态

kubectl get cs

显示:

NAME                 STATUS    MESSAGE              ERROR
controller-manager   Healthy   ok                   
scheduler            Healthy   ok                   
etcd-0               Healthy   {"health": "true"}   

查看pod状态

kubectl get pods --namespace=kube-system

显示:

可以看到coredns没有启动,这是由于还没有配置网络插件,接下来配置下后再重新查看启动状态

八、安装网络插件

1、配置flannel插件的yaml文件

cat > kube-flannel.yaml << EOF
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: flannel
rules:
  - apiGroups:
      - ""
    resources:
      - pods
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - nodes
    verbs:
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - nodes/status
    verbs:
      - patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: flannel
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: flannel
subjects:
- kind: ServiceAccount
  name: flannel
  namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: flannel
  namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
  name: kube-flannel-cfg
  namespace: kube-system
  labels:
    tier: node
    app: flannel
data:
  cni-conf.json: |
    {
      "name": "cbr0",
      "plugins": [
        {
          "type": "flannel",
          "delegate": {
            "hairpinMode": true,
            "isDefaultGateway": true
          }
        },
        {
          "type": "portmap",
          "capabilities": {
            "portMappings": true
          }
        }
      ]
    }
  net-conf.json: |
    {
      "Network": "10.20.0.0/16",
      "Backend": {
        "Type": "vxlan"
      }
    }
---
apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  name: kube-flannel-ds-amd64
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      hostNetwork: true
      nodeSelector:
        beta.kubernetes.io/arch: amd64
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: registry.cn-shenzhen.aliyuncs.com/cp_m/flannel:v0.10.0-amd64
        command:
        - cp
        args:
        - -f
        - /etc/kube-flannel/cni-conf.json
        - /etc/cni/net.d/10-flannel.conflist
        volumeMounts:
        - name: cni
          mountPath: /etc/cni/net.d
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      containers:
      - name: kube-flannel
        image: registry.cn-shenzhen.aliyuncs.com/cp_m/flannel:v0.10.0-amd64
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: true
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
        - name: run
          hostPath:
            path: /run
        - name: cni
          hostPath:
            path: /etc/cni/net.d
        - name: flannel-cfg
          configMap:
            name: kube-flannel-cfg
EOF

“Network”: “10.20.0.0/16”要和kubeadm-config.yaml配置文件中podSubnet: 10.20.0.0/16相同

2、创建flanner相关role和pod

kubectl apply -f kube-flannel.yaml

等待一会时间,再次查看各个pods的状态

kubectl get pods --namespace=kube-system

显示:

可以看到coredns已经启动

九、加入集群

1、Master加入集群构成高可用

复制秘钥到各个节点

在master01 服务器上执行下面命令,将kubernetes相关文件复制到 master02、master03

如果其他节点为初始化第一个master节点,则将该节点的配置文件复制到其余两个主节点,例如master03为第一个master节点,则将它的k8s配置复制到master02和master01。

  • 复制文件到 master02
ssh root@master02.k8s.io mkdir -p /etc/kubernetes/pki/etcd
scp /etc/kubernetes/admin.conf root@master02.k8s.io:/etc/kubernetes
scp /etc/kubernetes/pki/{ca.*,sa.*,front-proxy-ca.*} root@master02.k8s.io:/etc/kubernetes/pki
scp /etc/kubernetes/pki/etcd/ca.* root@master02.k8s.io:/etc/kubernetes/pki/etcd
  • 复制文件到 master03
ssh root@master03.k8s.io mkdir -p /etc/kubernetes/pki/etcd
scp /etc/kubernetes/admin.conf root@master03.k8s.io:/etc/kubernetes
scp /etc/kubernetes/pki/{ca.*,sa.*,front-proxy-ca.*} root@master03.k8s.io:/etc/kubernetes/pki
scp /etc/kubernetes/pki/etcd/ca.* root@master03.k8s.io:/etc/kubernetes/pki/etcd
  • master节点加入集群

master02 和 master03 服务器上都执行加入集群操作

kubeadm join master.k8s.io:16443 --token dm3cw1.kw4hq84ie1376hji --discovery-token-ca-cert-hash sha256:f079b624773145ba714b56e177f52143f90f75a1dcebabda6538a49e224d4009 --experimental-control-plane

如果加入失败想重新尝试,请输入 kubeadm reset 命令清除之前的设置,重新执行从“复制秘钥”和“加入集群”这两步

显示安装过程:

......
This node has joined the cluster and a new control plane instance was created:

* Certificate signing request was sent to apiserver and approval was received.
* The Kubelet was informed of the new secure connection details.
* Master label and taint were applied to the new node.
* The Kubernetes control plane instances scaled up.
* A new etcd member was added to the local/stacked etcd cluster.

To start administering your cluster from this node, you need to run the following as a regular user:

    mkdir -p $HOME/.kube
    sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
    sudo chown $(id -u):$(id -g) $HOME/.kube/config

Run 'kubectl get nodes' to see this node join the cluster.
  • 配置kubectl环境变量
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

2、node节点加入集群

除了让master节点加入集群组成高可用外,slave节点也要加入集群中。

这里将k8s-node-01、k8s-node-02加入集群,进行工作

输入初始化k8s master时候提示的加入命令,如下:

kubeadm join master.k8s.io:16443 --token dm3cw1.kw4hq84ie1376hji --discovery-token-ca-cert-hash sha256:f079b624773145ba714b56e177f52143f90f75a1dcebabda6538a49e224d4009

3、如果忘记加入集群的token和sha256 (如正常则跳过)

  • 显示获取token列表
kubeadm token list

默认情况下 Token 过期是时间是24小时,如果 Token 过期以后,可以输入以下命令,生成新的 Token

kubeadm token create
  • 获取ca证书sha256编码hash值
openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'
  • 拼接命令
kubeadm join master.k8s.io:16443 --token 882ik4.9ib2kb0eftvuhb58 --discovery-token-ca-cert-hash sha256:0b1a836894d930c8558b350feeac8210c85c9d35b6d91fde202b870f3244016a 

如果是master加入,请在最后面加上 –experimental-control-plane 这个参数

4、查看各个节点加入集群情况

kubectl get nodes -o wide

显示:

NAME            STATUS   ROLES    AGE   VERSION   INTERNAL-IP    EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION              CONTAINER-RUNTIME
k8s-master-01   Ready    master   12m   v1.13.4   192.168.2.11   <none>        CentOS Linux 7 (Core)   3.10.0-957.1.3.el7.x86_64   docker://18.6.1
k8s-master-02   Ready    master   10m   v1.13.4   192.168.2.12   <none>        CentOS Linux 7 (Core)   3.10.0-957.1.3.el7.x86_64   docker://18.6.1
k8s-master-03   Ready    master   38m   v1.13.4   192.168.2.13   <none>        CentOS Linux 7 (Core)   3.10.0-957.1.3.el7.x86_64   docker://18.6.1
k8s-node-01     Ready    <none>   68s   v1.13.4   192.168.2.21   <none>        CentOS Linux 7 (Core)   3.10.0-957.1.3.el7.x86_64   docker://18.6.1
k8s-node-02     Ready    <none>   61s   v1.13.4   192.168.2.22   <none>        CentOS Linux 7 (Core)   3.10.0-957.1.3.el7.x86_64   docker://18.6.1

十、从集群中删除 Node

  • Master节点:
kubectl drain <node name> --delete-local-data --force --ignore-daemonsets
kubectl delete node <node name>
  • slave节点
kubeadm reset

十一、配置dashboard

这个在一个服务器上部署,其他服务器会复制这个部署的pod,所以这里在master01服务器上部署 dashboard

1、创建 dashboard.yaml 并启动

# ------------------- Dashboard Secret ------------------- #
apiVersion: v1
kind: Secret
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard-certs
  namespace: kube-system
type: Opaque

---
# ------------------- Dashboard Service Account ------------------- #

apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kube-system

---
# ------------------- Dashboard Role & Role Binding ------------------- #

kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: kubernetes-dashboard-minimal
  namespace: kube-system
rules:
  # Allow Dashboard to create 'kubernetes-dashboard-key-holder' secret.
- apiGroups: [""]
  resources: ["secrets"]
  verbs: ["create"]
  # Allow Dashboard to create 'kubernetes-dashboard-settings' config map.
- apiGroups: [""]
  resources: ["configmaps"]
  verbs: ["create"]
  # Allow Dashboard to get, update and delete Dashboard exclusive secrets.
- apiGroups: [""]
  resources: ["secrets"]
  resourceNames: ["kubernetes-dashboard-key-holder", "kubernetes-dashboard-certs"]
  verbs: ["get", "update", "delete"]
  # Allow Dashboard to get and update 'kubernetes-dashboard-settings' config map.
- apiGroups: [""]
  resources: ["configmaps"]
  resourceNames: ["kubernetes-dashboard-settings"]
  verbs: ["get", "update"]
  # Allow Dashboard to get metrics from heapster.
- apiGroups: [""]
  resources: ["services"]
  resourceNames: ["heapster"]
  verbs: ["proxy"]
- apiGroups: [""]
  resources: ["services/proxy"]
  resourceNames: ["heapster", "http:heapster:", "https:heapster:"]
  verbs: ["get"]

---

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: kubernetes-dashboard-minimal
  namespace: kube-system
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: kubernetes-dashboard-minimal
subjects:
- kind: ServiceAccount
  name: kubernetes-dashboard
  namespace: kube-system

---

# ------------------- Dashboard Deployment ------------------- #
# 1.修改了镜像仓库位置,编辑成自己的镜像仓库
# 2.变更了镜像拉去策略imagePullPolicy: IfNotPresent
kind: Deployment
apiVersion: apps/v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kube-system
spec:
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      k8s-app: kubernetes-dashboard
  template:
    metadata:
      labels:
        k8s-app: kubernetes-dashboard
    spec:
      containers:
      - name: kubernetes-dashboard
        image: registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.10.1
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 8443
          protocol: TCP
        args:
          - --auto-generate-certificates
          # Uncomment the following line to manually specify Kubernetes API server Host
          # If not specified, Dashboard will attempt to auto discover the API server and connect
          # to it. Uncomment only if the default does not work.
          # - --apiserver-host=http://my-address:port
        volumeMounts:
        - name: kubernetes-dashboard-certs
          mountPath: /certs
          # Create on-disk volume to store exec logs
        - mountPath: /tmp
          name: tmp-volume
        livenessProbe:
          httpGet:
            scheme: HTTPS
            path: /
            port: 8443
          initialDelaySeconds: 30
          timeoutSeconds: 30
      volumes:
      - name: kubernetes-dashboard-certs
        secret:
          secretName: kubernetes-dashboard-certs
      - name: tmp-volume
        emptyDir: {}
      serviceAccountName: kubernetes-dashboard
      # Comment the following tolerations if Dashboard must not be deployed on master
      tolerations:
      - key: node-role.kubernetes.io/master
        effect: NoSchedule
---
# ------------------- Dashboard Service ------------------- #
# 增加了nodePort,使得能够访问,改变默认的type类型ClusterIP,变为NodePort
# 如果不配置的话默认只能集群内访问
kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kube-system
spec:
  type: NodePort
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 30001
  selector:
    k8s-app: kubernetes-dashboard

运行 dashboard

kubectl create -f kubernetes-dashboard.yaml

2、Dashboard 创建 ServiceAccount 并绑定 Admin 角色

kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: admin
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
roleRef:
  kind: ClusterRole
  name: cluster-admin
  apiGroup: rbac.authorization.k8s.io
subjects:
- kind: ServiceAccount
  name: admin
  namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin
  namespace: kube-system
  labels:
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile

运行dashboard的用户和角色绑定

kubectl create -f dashboard-user-role.yaml

获取登陆token

kubectl describe secret/$(kubectl get secret -n kube-system |grep admin|awk '{print $1}') -n kube-system

显示:

[root@k8s-master-01 local]# kubectl describe secret/$(kubectl get secret -nkube-system |grep admin|awk '{print $1}') -nkube-system
Name:         admin-token-2mfdz
Namespace:    kube-system
Labels:       <none>
Annotations:  kubernetes.io/service-account.name: admin
              kubernetes.io/service-account.uid: 74efd994-38d8-11e9-8740-000c299624e4

Type:  kubernetes.io/service-account-token

Data
====
ca.crt:     1025 bytes
namespace:  11 bytes

token:

eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJhZG1pbi10b2tlbi1qdjd4ayIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50Lm5hbWUiOiJhZG1pbiIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50LnVpZCI6ImM4ZTMxYzk0LTQ2MWEtMTFlOS1iY2M5LTAwMGMyOTEzYzUxZCIsInN1YiI6InN5c3RlbTpzZXJ2aWNlYWNjb3VudDprdWJlLXN5c3RlbTphZG1pbiJ9.TNw1iFEsZmJsVG4cki8iLtEoiY1pjpnOYm8ZIFjctpBdTOw6kUMvv2b2B2BJ_5rFle31gqGAZBIRyYj9LPAs06qT5uVP_l9o7IyFX4HToBF3veiun4e71822eQRUsgqiPh5uSjKXEkf9yGq9ujiCdtzFxnp3Pnpeuge73syuwd7J6F0-dJAp3b48MLZ1JJwEo6CTCMhm9buysycUYTbT_mUDQMNrHVH0868CdN_H8azA4PdLLLrFfTiVgoGu4c3sG5rgh9kKFqZA6dzV0Kq10W5JJwJRM1808ybLHyV9jfKN8N2_lZ7ehE6PbPU0cV-PyP74iA-HrzFW1yVwSLPVYA

3、运行dashboard并登陆

输入地址:https://192.168.2.10:30001 进入 dashboard 界面

这里输入上面获取的 token 进入 dashboard

问题

1、Master不会参与负载工作

Master不会参与负载工作,如何让其参加,这里需要了解traint

查看traint

# 查看全部节点是否能被安排工作
kubectl describe nodes | grep -E '(Roles|Taints)'

删除traint

# 所有node都可以调度
kubectl taint nodes --all node-role.kubernetes.io/master-
# 指定node可以调度
kubectl taint nodes k8s-master-01 node-role.kubernetes.io/master-

2、重新加入集群

有时候节点出现问题需要重新加入集群,加入前需要清除一些设置,不然可能出现某些错误,比如

network is not ready: [runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized]
Back-off restarting failed container 

按下面步骤执行,再执行加入集群命令即可

#重置kubernetes服务,重置网络。删除网络配置,link
kubeadm reset

#停止docker
systemctl stop docker

#重置cni
rm -rf /var/lib/cni/
rm -rf /var/lib/kubelet/*
rm -rf /etc/cni/
ifconfig cni0 down
ifconfig flannel.1 down
ifconfig docker0 down
ip link delete cni0
ip link delete flannel.1

#重启docker
systemctl start docker

再次加入集群

kubeadm join cluster.kube.com:16443 --token gaeyou.k2650x660c8eb98c --discovery-token-ca-cert-hash sha256:daf4c2e0264422baa7076a2587f9224a5bd9c5667307927b0238743799dfb362